This is a remix I made of the Glock and Sig Sauer P229 magazine speedloader, adapted to work with PSA Rock mags. I put it together last year after not finding any available at the time, so I customized an existing design from Thingiverse. It’s held up really well—both I and several friends have been using it for over a year without issues.

It may also fit Ruger 5.7 mags, though I haven’t been able to test that personally. I printed mine in PLA and it’s been solid so far, though PETG or ABS/ASA would likely be more durable, especially for outdoor use in sunlight. Tree supports work fine during printing, but feel free to use whatever setup you prefer.

I’ve also included the STEP file if you’d like to make your own modifications.